Coccydinia occurs when there is damage to your coccyx or the surrounding tissue. This causes pain and discomfort at the base of your spine, especially when you are sitting down.
Your coccyx can become damaged in several different ways, although in some cases of coccydinia, it may not be possible to identify a cause.
The various possible causes of coccydinia are outlined below.
Childbirth
Giving birth is the most common cause of coccydinia.
If you are pregnant, your coccyx will become more flexible towards the end of your third trimester (from week 27 to the birth) due to a release of hormones in your body. These hormones allow your coccyx and the part of your spine above it to bend and give way when you give birth to your baby.
However, in some cases, childbirth can cause the muscles and ligaments (stretchy tissue that connects bones) around your coccyx to overstretch. This means that these muscles and ligaments become permanently altered, and can no longer hold your coccyx in the right position, causing coccydinia.
Injury to your coccyx
Your coccyx can be injured in many different ways, such as falling from skis or ice skates, or landing on your coccyx from high up, such as off a horse.
You may also injure your coccyx if there is a hard impact to the area. For example, coccydinia has been known to occur after landing across the bar on a trampoline, or after a kick to the base of the spine.
In most cases of coccyx injury, your coccyx will only be badly bruised. However, if your coccyx is severely injured, it may be partly dislocated (moved out of joint) or fractured (broken). If this happens, the bones that make up your coccyx may move around and be painful, especially when you are sitting.
Repetitive strain injury (RSI)
You may get coccydinia if you regularly take part in sports such as cycling or rowing. This is due to the motion of continually leaning forward and stretching the base of your spine.
When this motion is repeated many times or the position is held for a long time, the muscles and ligaments (stretchy tissue that connects bones) around your coccyx can become strained and stretched.
This straining of your muscles and ligaments can result in them being permanently damaged. If this occurs, your muscles can no longer hold your coccyx in the right position. This causes pain and discomfort.
Poor posture
Sitting in an awkward position for long periods of time, such as at work or driving, can put excess pressure on your coccyx. This causes pain and discomfort that becomes worse the longer you stay in this position.
Being overweight or underweight
If you are obese or overweight, there may be excess pressure on your coccyx when you are sitting down. This can cause coccydinia, or make existing coccydinia worse.
However, you may also develop coccydinia if you are very slim. If this is the case, you may not have enough buttock fat to prevent your coccyx from rubbing against the tissues that surround it.
You can find out if you are the right weight for your height by using our body mass index (BMI) calculator. See the 'related articles' section for a link to the calculator.
Causes of secondary coccydinia
It is possible to develop coccydinia if you have pain higher up in your back, especially in the area just above your coccyx. This kind of back ache may be caused in many ways, including muscle tension, lifting or carrying incorrectly, or driving in a hunched position.
